//========================================================================
// GLFW 3.3 EGL - www.glfw.org
//------------------------------------------------------------------------
// Copyright (c) 2002-2006 Marcus Geelnard
// Copyright (c) 2006-2019 Camilla Löwy <elmindreda@glfw.org>
//
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not
//    claim that you wrote the original software. If you use this software
//    in a product, an acknowledgment in the product documentation would
//    be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such, and must not
//    be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source
//    distribution.
//
//========================================================================
// Please use C89 style variable declarations in this file because VS 2010
//========================================================================

#include "internal.h"

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>

// Return a description of the specified EGL error
//
static const char* getEGLErrorString(EGLint error) {
  switch (error) {
    case EGL_SUCCESS:
      return "Success";
    case EGL_NOT_INITIALIZED:
      return "EGL is not or could not be initialized";
    case EGL_BAD_ACCESS:
      return "EGL cannot access a requested resource";
    case EGL_BAD_ALLOC:
      return "EGL failed to allocate resources for the requested operation";
    case EGL_BAD_ATTRIBUTE:
      return "An unrecognized attribute or attribute value was passed in the attribute list";
    case EGL_BAD_CONTEXT:
      return "An EGLContext argument does not name a valid EGL rendering context";
    case EGL_BAD_CONFIG:
      return "An EGLConfig argument does not name a valid EGL frame buffer configuration";
    case EGL_BAD_CURRENT_SURFACE:
      return "The current surface of the calling thread is a window, pixel buffer or pixmap that is no longer valid";
    case EGL_BAD_DISPLAY:
      return "An EGLDisplay argument does not name a valid EGL display connection";
    case EGL_BAD_SURFACE:
      return "An EGLSurface argument does not name a valid surface configured for GL rendering";
    case EGL_BAD_MATCH:
      return "Arguments are inconsistent";
    case EGL_BAD_PARAMETER:
      return "One or more argument values are invalid";
    case EGL_BAD_NATIVE_PIXMAP:
      return "A NativePixmapType argument does not refer to a valid native pixmap";
    case EGL_BAD_NATIVE_WINDOW:
      return "A NativeWindowType argument does not refer to a valid native window";
    case EGL_CONTEXT_LOST:
      return "The application must destroy all contexts and reinitialise";
    default:
      return "ERROR: UNKNOWN EGL ERROR";
  }
}

// Returns the specified attribute of the specified EGLConfig
//
static int getEGLConfigAttrib(EGLConfig config, int attrib) {
  int value;
  eglGetConfigAttrib(_glfw.egl.display, config, attrib, &value);
  return value;
}

// Return the EGLConfig most closely matching the specified hints
//
static GLFWbool chooseEGLConfig(const _GLFWctxconfig* ctxconfig,
                                const _GLFWfbconfig* desired,
                                EGLConfig* result) {
  EGLConfig* nativeConfigs;
  _GLFWfbconfig* usableConfigs;
  const _GLFWfbconfig* closest;
  int i, nativeCount, usableCount;

  eglGetConfigs(_glfw.egl.display, NULL, 0, &nativeCount);
  if (!nativeCount) {
    _glfwInputError(GLFW_API_UNAVAILABLE, "EGL: No EGLConfigs returned");
    return GLFW_FALSE;
  }

  nativeConfigs = calloc(nativeCount, sizeof(EGLConfig));
  eglGetConfigs(_glfw.egl.display, nativeConfigs, nativeCount, &nativeCount);

  usableConfigs = calloc(nativeCount, sizeof(_GLFWfbconfig));
  usableCount = 0;

  for (i = 0; i < nativeCount; i++) {
    const EGLConfig n = nativeConfigs[i];
    _GLFWfbconfig* u = usableConfigs + usableCount;

    // Only consider RGB(A) EGLConfigs
    if (getEGLConfigAttrib(n, EGL_COLOR_BUFFER_TYPE) != EGL_RGB_BUFFER)
      continue;

    // Only consider window EGLConfigs
    if (!(getEGLConfigAttrib(n, EGL_SURFACE_TYPE) & EGL_WINDOW_BIT))
      continue;

#if defined(_GLFW_X11)
    {
      XVisualInfo vi = {0};

      // Only consider EGLConfigs with associated Visuals
      vi.visualid = getEGLConfigAttrib(n, EGL_NATIVE_VISUAL_ID);
      if (!vi.visualid)
        continue;

      if (desired->transparent) {
        int count;
        XVisualInfo* vis =
            XGetVisualInfo(_glfw.x11.display, VisualIDMask, &vi, &count);
        if (vis) {
          u->transparent = _glfwIsVisualTransparentX11(vis[0].visual);
          XFree(vis);
        }
      }
    }
#endif // _GLFW_X11

    if (ctxconfig->client == GLFW_OPENGL_ES_API) {
      if (ctxconfig->major == 1) {
        if (!(getEGLConfigAttrib(n, EGL_RENDERABLE_TYPE) & EGL_OPENGL_ES_BIT))
          continue;
      } else {
        if (!(getEGLConfigAttrib(n, EGL_RENDERABLE_TYPE) & EGL_OPENGL_ES2_BIT))
          continue;
      }
    } else if (ctxconfig->client == GLFW_OPENGL_API) {
      if (!(getEGLConfigAttrib(n, EGL_RENDERABLE_TYPE) & EGL_OPENGL_BIT))
        continue;
    }

    u->redBits = getEGLConfigAttrib(n, EGL_RED_SIZE);
    u->greenBits = getEGLConfigAttrib(n, EGL_GREEN_SIZE);
    u->blueBits = getEGLConfigAttrib(n, EGL_BLUE_SIZE);

    u->alphaBits = getEGLConfigAttrib(n, EGL_ALPHA_SIZE);
    u->depthBits = getEGLConfigAttrib(n, EGL_DEPTH_SIZE);
    u->stencilBits = getEGLConfigAttrib(n, EGL_STENCIL_SIZE);

    u->samples = getEGLConfigAttrib(n, EGL_SAMPLES);
    u->doublebuffer = desired->doublebuffer;

    u->handle = (uintptr_t)n;
    usableCount++;
  }

  closest = _glfwChooseFBConfig(desired, usableConfigs, usableCount);
  if (closest)
    *result = (EGLConfig)closest->handle;

  free(nativeConfigs);
  free(usableConfigs);

  return closest != NULL;
}

static void makeContextCurrentEGL(_GLFWwindow* window) {
  if (window) {
    if (!eglMakeCurrent(_glfw.egl.display,
                        window->context.egl.surface,
                        window->context.egl.surface,
                        window->context.egl.handle)) {
      _glfwInputError(GLFW_PLATFORM_ERROR,
                      "EGL: Failed to make context current: %s",
                      getEGLErrorString(eglGetError()));
      return;
    }
  } else {
    if (!eglMakeCurrent(_glfw.egl.display,
                        EGL_NO_SURFACE,
                        EGL_NO_SURFACE,
                        EGL_NO_CONTEXT)) {
      _glfwInputError(GLFW_PLATFORM_ERROR,
                      "EGL: Failed to clear current context: %s",
                      getEGLErrorString(eglGetError()));
      return;
    }
  }

  _glfwPlatformSetTls(&_glfw.contextSlot, window);
}

static void swapBuffersEGL(_GLFWwindow* window) {
  if (window != _glfwPlatformGetTls(&_glfw.contextSlot)) {
    _glfwInputError(GLFW_PLATFORM_ERROR,
                    "EGL: The context must be current on the calling thread when swapping buffers");
    return;
  }

  eglSwapBuffers(_glfw.egl.display, window->context.egl.surface);
}

static void swapIntervalEGL(int interval) {
  eglSwapInterval(_glfw.egl.display, interval);
}

static int extensionSupportedEGL(const char* extension) {
  const char* extensions = eglQueryString(_glfw.egl.display, EGL_EXTENSIONS);
  if (extensions) {
    if (_glfwStringInExtensionString(extension, extensions))
      return GLFW_TRUE;
  }

  return GLFW_FALSE;
}

static GLFWglproc getProcAddressEGL(const char* procname) {
  _GLFWwindow* window = _glfwPlatformGetTls(&_glfw.contextSlot);

  if (window->context.egl.client) {
    GLFWglproc proc = (GLFWglproc)_glfw_dlsym(window->context.egl.client,
                                              procname);
    if (proc)
      return proc;
  }

  return eglGetProcAddress(procname);
}

static void destroyContextEGL(_GLFWwindow* window) {
#if defined(_GLFW_X11)
  // NOTE: Do not unload libGL.so.1 while the X11 display is still open,
  //       as it will make XCloseDisplay segfault
  if (window->context.client != GLFW_OPENGL_API)
#endif // _GLFW_X11
  {
    if (window->context.egl.client) {
      _glfw_dlclose(window->context.egl.client);
      window->context.egl.client = NULL;
    }
  }

  if (window->context.egl.surface) {
    eglDestroySurface(_glfw.egl.display, window->context.egl.surface);
    window->context.egl.surface = EGL_NO_SURFACE;
  }

  if (window->context.egl.handle) {
    eglDestroyContext(_glfw.egl.display, window->context.egl.handle);
    window->context.egl.handle = EGL_NO_CONTEXT;
  }
}

//////////////////////////////////////////////////////////////////////////
//////                       GLFW internal API                      //////
//////////////////////////////////////////////////////////////////////////

// Initialize EGL
//
GLFWbool _glfwInitEGL(void) {
  int i;
  const char* sonames[] =
  {
#if defined(_GLFW_EGL_LIBRARY)
    _GLFW_EGL_LIBRARY,
#elif defined(_GLFW_WIN32)
    "libEGL.dll",
    "EGL.dll",
#elif defined(_GLFW_COCOA)
    "libEGL.dylib",
#elif defined(__CYGWIN__)
    "libEGL-1.so",
#else
    "libEGL.so.1",
#endif
    NULL
  };

  if (_glfw.egl.handle)
    return GLFW_TRUE;

  for (i = 0; sonames[i]; i++) {
    _glfw.egl.handle = _glfw_dlopen(sonames[i]);
    if (_glfw.egl.handle)
      break;
  }

  if (!_glfw.egl.handle) {
    _glfwInputError(GLFW_API_UNAVAILABLE, "EGL: Library not found");
    return GLFW_FALSE;
  }

  _glfw.egl.prefix = (strncmp(sonames[i], "lib", 3) == 0);

  _glfw.egl.GetConfigAttrib = (PFN_eglGetConfigAttrib)
      _glfw_dlsym(_glfw.egl.handle, "eglGetConfigAttrib");
  _glfw.egl.GetConfigs = (PFN_eglGetConfigs)
      _glfw_dlsym(_glfw.egl.handle, "eglGetConfigs");
  _glfw.egl.GetDisplay = (PFN_eglGetDisplay)
      _glfw_dlsym(_glfw.egl.handle, "eglGetDisplay");
  _glfw.egl.GetError = (PFN_eglGetError)
      _glfw_dlsym(_glfw.egl.handle, "eglGetError");
  _glfw.egl.Initialize = (PFN_eglInitialize)
      _glfw_dlsym(_glfw.egl.handle, "eglInitialize");
  _glfw.egl.Terminate = (PFN_eglTerminate)
      _glfw_dlsym(_glfw.egl.handle, "eglTerminate");
  _glfw.egl.BindAPI = (PFN_eglBindAPI)
      _glfw_dlsym(_glfw.egl.handle, "eglBindAPI");
  _glfw.egl.CreateContext = (PFN_eglCreateContext)
      _glfw_dlsym(_glfw.egl.handle, "eglCreateContext");
  _glfw.egl.DestroySurface = (PFN_eglDestroySurface)
      _glfw_dlsym(_glfw.egl.handle, "eglDestroySurface");
  _glfw.egl.DestroyContext = (PFN_eglDestroyContext)
      _glfw_dlsym(_glfw.egl.handle, "eglDestroyContext");
  _glfw.egl.CreateWindowSurface = (PFN_eglCreateWindowSurface)
      _glfw_dlsym(_glfw.egl.handle, "eglCreateWindowSurface");
  _glfw.egl.MakeCurrent = (PFN_eglMakeCurrent)
      _glfw_dlsym(_glfw.egl.handle, "eglMakeCurrent");
  _glfw.egl.SwapBuffers = (PFN_eglSwapBuffers)
      _glfw_dlsym(_glfw.egl.handle, "eglSwapBuffers");
  _glfw.egl.SwapInterval = (PFN_eglSwapInterval)
      _glfw_dlsym(_glfw.egl.handle, "eglSwapInterval");
  _glfw.egl.QueryString = (PFN_eglQueryString)
      _glfw_dlsym(_glfw.egl.handle, "eglQueryString");
  _glfw.egl.GetProcAddress = (PFN_eglGetProcAddress)
      _glfw_dlsym(_glfw.egl.handle, "eglGetProcAddress");

  if (!_glfw.egl.GetConfigAttrib ||
      !_glfw.egl.GetConfigs ||
      !_glfw.egl.GetDisplay ||
      !_glfw.egl.GetError ||
      !_glfw.egl.Initialize ||
      !_glfw.egl.Terminate ||
      !_glfw.egl.BindAPI ||
      !_glfw.egl.CreateContext ||
      !_glfw.egl.DestroySurface ||
      !_glfw.egl.DestroyContext ||
      !_glfw.egl.CreateWindowSurface ||
      !_glfw.egl.MakeCurrent ||
      !_glfw.egl.SwapBuffers ||
      !_glfw.egl.SwapInterval ||
      !_glfw.egl.QueryString ||
      !_glfw.egl.GetProcAddress) {
    _glfwInputError(GLFW_PLATFORM_ERROR,
                    "EGL: Failed to load required entry points");

    _glfwTerminateEGL();
    return GLFW_FALSE;
  }

  _glfw.egl.display = eglGetDisplay(_GLFW_EGL_NATIVE_DISPLAY);
  if (_glfw.egl.display == EGL_NO_DISPLAY) {
    _glfwInputError(GLFW_API_UNAVAILABLE,
                    "EGL: Failed to get EGL display: %s",
                    getEGLErrorString(eglGetError()));

    _glfwTerminateEGL();
    return GLFW_FALSE;
  }

  if (!eglInitialize(_glfw.egl.display, &_glfw.egl.major, &_glfw.egl.minor)) {
    _glfwInputError(GLFW_API_UNAVAILABLE,
                    "EGL: Failed to initialize EGL: %s",
                    getEGLErrorString(eglGetError()));

    _glfwTerminateEGL();
    return GLFW_FALSE;
  }

  _glfw.egl.KHR_create_context =
      extensionSupportedEGL("EGL_KHR_create_context");
  _glfw.egl.KHR_create_context_no_error =
      extensionSupportedEGL("EGL_KHR_create_context_no_error");
  _glfw.egl.KHR_gl_colorspace =
      extensionSupportedEGL("EGL_KHR_gl_colorspace");
  _glfw.egl.KHR_get_all_proc_addresses =
      extensionSupportedEGL("EGL_KHR_get_all_proc_addresses");
  _glfw.egl.KHR_context_flush_control =
      extensionSupportedEGL("EGL_KHR_context_flush_control");

  return GLFW_TRUE;
}

// Terminate EGL
//
void _glfwTerminateEGL(void) {
  if (_glfw.egl.display) {
    eglTerminate(_glfw.egl.display);
    _glfw.egl.display = EGL_NO_DISPLAY;
  }

  if (_glfw.egl.handle) {
    _glfw_dlclose(_glfw.egl.handle);
    _glfw.egl.handle = NULL;
  }
}

#define setAttrib(a, v) \
  { \
    assert(((size_t)index + 1) < sizeof(attribs) / sizeof(attribs[0])); \
    attribs[index++] = a; \
    attribs[index++] = v; \
  }

// Create the OpenGL or OpenGL ES context
//
GLFWbool _glfwCreateContextEGL(_GLFWwindow* window,
                               const _GLFWctxconfig* ctxconfig,
                               const _GLFWfbconfig* fbconfig) {
  EGLint attribs[40];
  EGLConfig config;
  EGLContext share = NULL;
  int index = 0;

  if (!_glfw.egl.display) {
    _glfwInputError(GLFW_API_UNAVAILABLE, "EGL: API not available");
    return GLFW_FALSE;
  }

  if (ctxconfig->share)
    share = ctxconfig->share->context.egl.handle;

  if (!chooseEGLConfig(ctxconfig, fbconfig, &config)) {
    _glfwInputError(GLFW_FORMAT_UNAVAILABLE,
                    "EGL: Failed to find a suitable EGLConfig");
    return GLFW_FALSE;
  }

  if (ctxconfig->client == GLFW_OPENGL_ES_API) {
    if (!eglBindAPI(EGL_OPENGL_ES_API)) {
      _glfwInputError(GLFW_API_UNAVAILABLE,
                      "EGL: Failed to bind OpenGL ES: %s",
                      getEGLErrorString(eglGetError()));
      return GLFW_FALSE;
    }
  } else {
    if (!eglBindAPI(EGL_OPENGL_API)) {
      _glfwInputError(GLFW_API_UNAVAILABLE,
                      "EGL: Failed to bind OpenGL: %s",
                      getEGLErrorString(eglGetError()));
      return GLFW_FALSE;
    }
  }

  if (_glfw.egl.KHR_create_context) {
    int mask = 0, flags = 0;

    if (ctxconfig->client == GLFW_OPENGL_API) {
      if (ctxconfig->forward)
        flags |= EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR;

      if (ctxconfig->profile == GLFW_OPENGL_CORE_PROFILE)
        mask |= EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT_KHR;
      else if (ctxconfig->profile == GLFW_OPENGL_COMPAT_PROFILE)
        mask |= EGL_CONTEXT_OPENGL_COMPATIBILITY_PROFILE_BIT_KHR;
    }

    if (ctxconfig->debug)
      flags |= EGL_CONTEXT_OPENGL_DEBUG_BIT_KHR;

    if (ctxconfig->robustness) {
      if (ctxconfig->robustness == GLFW_NO_RESET_NOTIFICATION) {
        setAttrib(EGL_CONTEXT_OPENGL_RESET_NOTIFICATION_STRATEGY_KHR,
                  EGL_NO_RESET_NOTIFICATION_KHR);
      } else if (ctxconfig->robustness == GLFW_LOSE_CONTEXT_ON_RESET) {
        setAttrib(EGL_CONTEXT_OPENGL_RESET_NOTIFICATION_STRATEGY_KHR,
                  EGL_LOSE_CONTEXT_ON_RESET_KHR);
      }

      flags |= EGL_CONTEXT_OPENGL_ROBUST_ACCESS_BIT_KHR;
    }

    if (ctxconfig->noerror) {
      if (_glfw.egl.KHR_create_context_no_error)
        setAttrib(EGL_CONTEXT_OPENGL_NO_ERROR_KHR, GLFW_TRUE);
    }

    if (ctxconfig->major != 1 || ctxconfig->minor != 0) {
      setAttrib(EGL_CONTEXT_MAJOR_VERSION_KHR, ctxconfig->major);
      setAttrib(EGL_CONTEXT_MINOR_VERSION_KHR, ctxconfig->minor);
    }

    if (mask)
      setAttrib(EGL_CONTEXT_OPENGL_PROFILE_MASK_KHR, mask);

    if (flags)
      setAttrib(EGL_CONTEXT_FLAGS_KHR, flags);
  } else {
    if (ctxconfig->client == GLFW_OPENGL_ES_API)
      setAttrib(EGL_CONTEXT_CLIENT_VERSION, ctxconfig->major);
  }

  if (_glfw.egl.KHR_context_flush_control) {
    if (ctxconfig->release == GLFW_RELEASE_BEHAVIOR_NONE) {
      setAttrib(EGL_CONTEXT_RELEASE_BEHAVIOR_KHR,
                EGL_CONTEXT_RELEASE_BEHAVIOR_NONE_KHR);
    } else if (ctxconfig->release == GLFW_RELEASE_BEHAVIOR_FLUSH) {
      setAttrib(EGL_CONTEXT_RELEASE_BEHAVIOR_KHR,
                EGL_CONTEXT_RELEASE_BEHAVIOR_FLUSH_KHR);
    }
  }

  setAttrib(EGL_NONE, EGL_NONE);

  window->context.egl.handle = eglCreateContext(_glfw.egl.display,
                                                config,
                                                share,
                                                attribs);

  if (window->context.egl.handle == EGL_NO_CONTEXT) {
    _glfwInputError(GLFW_VERSION_UNAVAILABLE,
                    "EGL: Failed to create context: %s",
                    getEGLErrorString(eglGetError()));
    return GLFW_FALSE;
  }

  // Set up attributes for surface creation
  index = 0;

  if (fbconfig->sRGB) {
    if (_glfw.egl.KHR_gl_colorspace)
      setAttrib(EGL_GL_COLORSPACE_KHR, EGL_GL_COLORSPACE_SRGB_KHR);
  }

  if (!fbconfig->doublebuffer)
    setAttrib(EGL_RENDER_BUFFER, EGL_SINGLE_BUFFER);

  setAttrib(EGL_NONE, EGL_NONE);

  window->context.egl.surface =
      eglCreateWindowSurface(_glfw.egl.display,
                             config,
                             _GLFW_EGL_NATIVE_WINDOW,
                             attribs);
  if (window->context.egl.surface == EGL_NO_SURFACE) {
    _glfwInputError(GLFW_PLATFORM_ERROR,
                    "EGL: Failed to create window surface: %s",
                    getEGLErrorString(eglGetError()));
    return GLFW_FALSE;
  }

  window->context.egl.config = config;

  // Load the appropriate client library
  if (!_glfw.egl.KHR_get_all_proc_addresses) {
    int i;
    const char** sonames;
    const char* es1sonames[] =
    {
#if defined(_GLFW_GLESV1_LIBRARY)
      _GLFW_GLESV1_LIBRARY,
#elif defined(_GLFW_WIN32)
      "GLESv1_CM.dll",
      "libGLES_CM.dll",
#elif defined(_GLFW_COCOA)
      "libGLESv1_CM.dylib",
#else
      "libGLESv1_CM.so.1",
      "libGLES_CM.so.1",
#endif
      NULL
    };
    const char* es2sonames[] =
    {
#if defined(_GLFW_GLESV2_LIBRARY)
      _GLFW_GLESV2_LIBRARY,
#elif defined(_GLFW_WIN32)
      "GLESv2.dll",
      "libGLESv2.dll",
#elif defined(_GLFW_COCOA)
      "libGLESv2.dylib",
#elif defined(__CYGWIN__)
      "libGLESv2-2.so",
#else
      "libGLESv2.so.2",
#endif
      NULL
    };
    const char* glsonames[] =
    {
#if defined(_GLFW_OPENGL_LIBRARY)
      _GLFW_OPENGL_LIBRARY,
#elif defined(_GLFW_WIN32)
#elif defined(_GLFW_COCOA)
#else
      "libGL.so.1",
#endif
      NULL
    };

    if (ctxconfig->client == GLFW_OPENGL_ES_API) {
      if (ctxconfig->major == 1)
        sonames = es1sonames;
      else
        sonames = es2sonames;
    } else
      sonames = glsonames;

    for (i = 0; sonames[i]; i++) {
      // HACK: Match presence of lib prefix to increase chance of finding
      //       a matching pair in the jungle that is Win32 EGL/GLES
      if (_glfw.egl.prefix != (strncmp(sonames[i], "lib", 3) == 0))
        continue;

      window->context.egl.client = _glfw_dlopen(sonames[i]);
      if (window->context.egl.client)
        break;
    }

    if (!window->context.egl.client) {
      _glfwInputError(GLFW_API_UNAVAILABLE,
                      "EGL: Failed to load client library");
      return GLFW_FALSE;
    }
  }

  window->context.makeCurrent = makeContextCurrentEGL;
  window->context.swapBuffers = swapBuffersEGL;
  window->context.swapInterval = swapIntervalEGL;
  window->context.extensionSupported = extensionSupportedEGL;
  window->context.getProcAddress = getProcAddressEGL;
  window->context.destroy = destroyContextEGL;

  return GLFW_TRUE;
}

#undef setAttrib

// Returns the Visual and depth of the chosen EGLConfig
//
#if defined(_GLFW_X11)
GLFWbool _glfwChooseVisualEGL(const _GLFWwndconfig* wndconfig,
                              const _GLFWctxconfig* ctxconfig,
                              const _GLFWfbconfig* fbconfig,
                              Visual** visual, int* depth) {
  XVisualInfo* result;
  XVisualInfo desired;
  EGLConfig native;
  EGLint visualID = 0, count = 0;
  const long vimask = VisualScreenMask | VisualIDMask;

  if (!chooseEGLConfig(ctxconfig, fbconfig, &native)) {
    _glfwInputError(GLFW_FORMAT_UNAVAILABLE,
                    "EGL: Failed to find a suitable EGLConfig");
    return GLFW_FALSE;
  }

  eglGetConfigAttrib(_glfw.egl.display, native, EGL_NATIVE_VISUAL_ID, &visualID);

  desired.screen = _glfw.x11.screen;
  desired.visualid = visualID;

  result = XGetVisualInfo(_glfw.x11.display, vimask, &desired, &count);
  if (!result) {
    _glfwInputError(GLFW_PLATFORM_ERROR,
                    "EGL: Failed to retrieve Visual for EGLConfig");
    return GLFW_FALSE;
  }

  *visual = result->visual;
  *depth = result->depth;

  XFree(result);
  return GLFW_TRUE;
}
#endif // _GLFW_X11

//////////////////////////////////////////////////////////////////////////
//////                        GLFW native API                       //////
//////////////////////////////////////////////////////////////////////////

GLFWAPI EGLDisplay glfwGetEGLDisplay(void) {
  _GLFW_REQUIRE_INIT_OR_RETURN(EGL_NO_DISPLAY);
  return _glfw.egl.display;
}

GLFWAPI EGLContext glfwGetEGLContext(GLFWwindow* handle) {
  _GLFWwindow* window = (_GLFWwindow*)handle;
  _GLFW_REQUIRE_INIT_OR_RETURN(EGL_NO_CONTEXT);

  if (window->context.client == GLFW_NO_API) {
    _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
    return EGL_NO_CONTEXT;
  }

  return window->context.egl.handle;
}

GLFWAPI EGLSurface glfwGetEGLSurface(GLFWwindow* handle) {
  _GLFWwindow* window = (_GLFWwindow*)handle;
  _GLFW_REQUIRE_INIT_OR_RETURN(EGL_NO_SURFACE);

  if (window->context.client == GLFW_NO_API) {
    _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
    return EGL_NO_SURFACE;
  }

  return window->context.egl.surface;
}
